<?php
session_start();
session_register("verifyCode");
$_SESSION["verifyCode"] = mt_rand(0000,9999);
Header("Content-type:image/gif");
$im = imageCreate(40,20);
$white = imageColorAllocate($im,255,255,255);
$black = imageColorAllocate($im,0,0,0);
imageString($im,10,0,5,$_SESSION["verifyCode"],$black);
imageJpeg($im);
imagedestroy($im);
?>
